I am having issues connecting to Xbox Live. More accurately I am having problems staying connected to Xbox Live. I can connect to it just fine, for 5 or 10 seconds. After that time I am disconnected. I have tested my wireless network rather extensively with a laptop. Even to the point of using a packet sniffer to ensure there are no problems in the packet structures to and from the router. From the standpoint of the laptop, everything works perfectly. I have also gone through the sticky posts above and run their troubleshooting steps. These did not help. I have also found references to the NAT issue every admin seems to be replying with right now. This is not the problem. Even borrowed a "dumb" modem to try that step. Did not help.
The current setup was working great just a few days ago. There have been no changes to the network structure. The only major change was I applied a recent patch to Xbox. I haven't even installed new applications on my PC since the Xbox was working fine, to how it works now.